Local government in Mount Gambier was established in 1863, when the District Council of Mount Gambier met for the first time, and Edward Wehl was elected the inaugural chairman.
In December 1864 the District Council of Mount Gambier was divided into the District Council of Mount Gambier West (Town Council) and the District Council of Mount Gambier East. In May 1876 another division occurred resulting in the formation of the first town council with John Watson as Mayor.[8]

The three local governments operated independently up until 1932 when the District Council of Mount Gambier West and District Council of Mount Gambier East were merged to once again be united under the banner of the District Council of Mount Gambier.
The town council never merged back, instead becoming what is now the City of Mount Gambier.[8]

By the end of the 1860s there were enough people in town and surrounding smaller settlements to warrant the proclamation of the District Council of Port MacDonnell.[9]

With Port MacDonnell being the second largest port in South Australia, the population held steady until the decision was made not to connect the port to the newly south east railway network. This resulted in loss of trade, and declining populations in the town.[9]

The two councils merged in 1996 to form the District Council of Grant.[10]